Organic light-emitting diodes (OLEDs) have the potential for providing inexpensive alternatives to LEDs. OLEDs may be fabricated by coating the appropriate surfaces with the organic material either from solution or by using conventional vacuum deposition techniques, and hence, do not require the use of high cost fabrication systems such as those utilized in the fabrication of semiconductor devices. A simple OLED may be constructed from an electroluminescent layer sandwiched between an electron injection electrode and a hole injection electrode. More complicated devices utilize electron and hole transport layers between the above mentioned electrodes and the electroluminescent layer.
Addressable color displays may be constructed from OLEDs if individual OLEDs having three primary colors can be constructed. The individual OLEDs must have the same operating voltages. Hence, OLEDs that are constructed from a common light emitting layer which is doped with compounds to set the color are preferred, provided the dopants do not alter the operating voltage.
Unfortunately, compounds having high efficiency and satisfactory lifetimes for constructing OLEDs that emit in the red portion of the spectrum are lacking.
Broadly, it is the object of the present invention to provide an improved OLED.
It is a further object of the present invention to provide a set of OLEDs that can be utilized in constructing a color display, and more particularly in the red portion of the spectrum.
It is a still further object of the present invention to provide an OLED that has higher quantum efficiency than prior art OLEDs.
It is yet another object of the present invention to provide an OLED dopant material that does not alter the operating voltage of the OLED while providing emission in the red portion of the spectrum.
These and other objects of the present invention will become apparent to those skilled in the art from the following detailed description of the invention and the accompanying drawings.